A METHOD AND COMPUTER PROVIDED WTIH MEANS FOR REMOTE COMMUNICATION VIA A TELEPHONE NETWORK USING A WIRE MODE OR A RADIO MODE

Abstract: A computer suitable for remote communication via a telephone network comprises in combination: a computer unit (11); a modem (12) connected to the computer unit and suitable for being connected to the telephone network via a cord (12a); a transmitter/receiver circuit (14) suitable for establishing calls by radio with a remote site, likewise for accessing the network; a control circuit (13) for the transmitter/receiver circuit; means provided in the computer for applying commands to the modem from a predefined set of commands; cord call determining means provided in the computer for determining whether a telephone call via the cord is desired or in progress, and for producing a signal; means either for processing commands received in the modem or else for converting them into specific commands for the control circuit as a function of said signal; and means provided in said control circuit for processing said specific commands. The invention also provides a method for being implemented by the computer.

Description: A METHOD AND COMPUTER PROVIDED WITH MEANS FOR REMOTE COMMUNICATION VIA A TELEPHONE NETWORK USING A WIRE MODE OR A RADIO MODE The present invention relates in general to computers that are fitted with means for remote communication via a telephone network, and in particular to portable personal computers. Conventionally, such a computer is fitted with a modem enabling it to modulate digital data onto signals that are suitable for being conveyed over a telephone network and to demodulate digital data from such signals. The modem is connected to the telephone network by a cord. In the field of radiotelephony, a system is also known that enables a call to be established with a public telephone network after a radio link has initially been established between a cordless portable telephone set and a base station (access point) situated at some acceptable distance from the telephone. In particular, there exists the so-called "CT2" standard which is identified more clearly below and to which reference may be made for full details, and manufacturers are now proposing electronic modules or components suitable for establishing radio links in compliance with that standard. The present invention relates to a computer capable of remote communication via the public telephone network equally well by means of a cord connected to the network and by means of a radio link, e.g. in compliance with the above-specified standard. WO-A-91 07044 discloses software protocols that are used to handle cellular specific carrier loss and calling delays, as well as the packetised transfer of data, with transmission retries for corrupted packets. However, there is no mention at all of the cooperation of a host modem in a computer with a radio system in order to obtain a transparent operation from the user's standpoint. US-A-5 127 041 describes a set of customized cables for attaching a computer to a cellular or other phone system. However, such system is very fastidious for the user, because switching from a landline communication to a radio communication requires a number of manual operations such as cable connection. Therefore, there is no transparency at all from the user's standpoint. An object of the present invention is to propose such a computer in which a call can be established in either of those two modes without the software in the computer which is making use of such calls needing any special adaptation. In particular, the invention seeks to handle modes of access to the network in a manner that is transparent for the computer user. To this end, the invention provides a computer, in particular a portable personal computer, suitable for remote communication via a telephone network, characterized in that it comprises in combination: a computer unit including a central processor, storage means, input/output means, and means for inputting and displaying data; a modem connected to the computer unit and suitable for being connected to the telephone network via a cord; a transmitter/receiver circuit suitable for establishing calls by radio with a remote site, likewise for accessing the telephone network; a control circuit for the transmitter/receiver circuit; means provided in the computer for applying commands to the modem as selected from a predefined set of commands; cord call determining means provided in the computer for determining whether a telephone call via the cord is desired or in progress, and for producing a corresponding signal; means provided in the computer either for processing commands received in the modem or else for converting said received commands into specific commands for the control circuit and for applying these specific commands to the control circuit as a function of said signal; and means provided in said control circuit for processing said specific commands. Preferred, but non-limiting aspects of the computer of the present invention are as follows: said transmitter/receiver circuit is suitable for accessing said telephone network by previously establishing a radio link with a base station; the cord call determining means are provided in the modem; the cord call determining means comprise detection means for detecting connection of the cord to the modem; said detection means are constituted by means for determining the presence of a country identifier in said cord; each of said specific commands comprises: a common prefix; information representative of the fact that said command is a specific command; and a command identifier; said common prefix is identical to a common prefix for commands belonging to said predefined command set; the control circuit is originally designed for receiving manual instructions from a user producing instruction signals, one of said specific commands includes a command identifier followed by a string of characters, said identifier being representative of manual instruction simulation, and the control circuit is suitable for processing said characters of said string as though they constitute instruction signals resulting from giving manual instructions; said manual instructions are constituted by keypresses performed on a keypad; said string of characters is representative of a number to be dialed; said characters are in ASCII format; said control circuit is originally designed to control display means, the control circuit is suitable for transmitting a message to the modem that includes a string of characters representative of information to be displayed on the display means, and the computer includes means for processing said character; the means for processing said characters comprise means for providing a display on the basis of said characters; the modem includes means for detecting an incoming ringing signal, and the control circuit includes means for generating a simulated ringing signal and for applying it to the modem; and the computer further includes switching means for switching commands under the control of the control circuit and suitable for selectively applying to an analog signal input terminal of the modem either said generated simulated ringing signal or else analog signals as received by said transmitter/receiver circuit. In another aspect, the invention provides a method for use in a computer, in particular a portable personal computer, comprising: a computer unit including a central processor, storage means, input/output means, and means for inputting and displaying data; a modem connected to the computer unit and capable of being connected to a telephone network via a cord; a transmitter/receiver circuit suitable for establishing radio calls with a remote site; a control circuit for controlling the transmitter/receiver circuit; and means provided in the computer for applying commands to the modem, which commands are selected from a predefined set of commands, the method being intended to set up a remote call via said telephone network and being characterized by the following steps: it is determined whether a telephone call via the cord is requested or is in progress, and a corresponding signal is produced; as a function of said signal, either received commands are processed in the modem, or else the received commands are converted into specific commands for the control circuit and said specific commands are applied to the control circuit; and said specific commands are processed in said control circuit. Other aspects, objects, and advantages of the present invention appear more clearly on reading the following detailed description of a preferred embodiment, given by way of example and made with reference to the accompanying drawings, in which: Figure 1 is a block diagram of a computer of the invention; Figure 2 shows a detail of the Figure 1 computer; Figure 3 shows another detail of the Figure 1 computer; and Figure 4 shows two operating modes of a component of the computer. With reference initially to Figure 1, there can be seen a portable personal computer 10 comprising the components that are conventional for such a computer, namely: a central processor unit, a read-only memory, a read/write memory, input/output circuits, mass storage devices, a data input device such as a keyboard, and data display means such as a liquid crystal display screen, for example. These elements are given overall reference 11. The computer may be a "PowerBook" (registered trademark) model as manufactured by Apple Computer Inc. The computer 10 also includes a modem card 12 connected to the portion 11 by a suitable connector. For example, the modem card may be the "PowerBook Express Modem" also manufactured by Apple Computer Inc. It constitutes an intelligent modem card controlled by a microcontroller and by a resident program. The modem card 12 may be connected to the Public Telephone network (PTN) by a cord 12a. The modem card is also equipped to read an electrical parameter from the connector of the cord representative of the identifier of a country for which the cord is adapted, and to adapt its own operating parameters as a function of the telephone regulations applicable to that country. Further details concerning that device can be obtained by referring to Documents FR-A-2 652 173 and FR-A-2 677 831 in the name of the Applicant. In the context of the present invention, this country identification process is also used to determine whether a telephone call via the cord is possible or is in progress. 13 designates a radio call controller and 14 an associated transmitter/receiver circuit under its control. In the present example, these elements are made in compliance with the standard ESTI 300-131, commonly referred to as CT2 for "Cordless Telephone 2". The radio call controller 13 is governed by a microcontroller and by a resident program. The controller 13 is connected to the modem 12 by a serial link, as described in detail below. According to an aspect of the present invention, all of the call commands, and in particular commands taken from a standardized set commonly known as the "AT" commands, are applied to the modem 12 independently of the communications mode used, as described in detail below. In conventional manner, the modem 12 performs the modulation and demodulation processes and it handles high level protocols such as the following standard protocols: T30, MNP, and V42. The controller 13 performs low level functions, in particular line access and line handling. According to another aspect of the present invention, the modem 12 is capable of controlling the controller 13 by means of a pre-established set of specific commands. As mentioned above, when a telephone call is to be established, the resident program in the modem 12 is designed initially to verify whether the cord 12a is connected to the modem 12. If it is, then the commands of the above-specified standard set ("AT" commands) are processed normally by the modem. If it is not connected, then the program in the modem is designed to convert the commands it receives from the computer into corresponding commands for the circuits 13 and 14, which commands belong to the above-specified specific set. In this way, existing applications that use telephone communications can be used in a computer of the present invention without needing to be rewritten, with selection between conventional network access via a cord and access to the same network via a radio link and a base station (also called an "access point") taking place in a manner that is transparent for the application. In a variant, selection of the link mode to be used, i.e. by wire or by radio, may be performed at the initiative of the user, but in principle, the presence of the cord is always verified. If the controller circuit 13 is derived directly from a circuit designed for fitting to a portable radio telephone, i.e. if it is designed to process instructions that come essentially from pressing specific keys on a keypad, then it is preferable to provide a specific command for emulating such a keypress or keypresses. More particularly, the resident program in the controller 13 is designed to interpret such a command exactly as if a user of a portable radio telephone had pressed a key on the keypad corresponding to a keypress identifier that follows the command. This keypad emulation command is described in detail below. With reference now to Figure 2, the hardware of the interface between the modem 12 and the controller 13 is described. This interface is preferably a conventional serial interface such as the "SCI" interface (Serial Communication Interface), operating in asynchronous mode. That interface has two lines LI and L2, respectively for transmitting and receiving analog audio signals, a line L3 acting as an auxiliary input/output line, and an on/off control line L4. Preferably, the logic of the modem 12 and the logic of the controller circuit 13 are designed so that when the modem seeks to send a command to the controller, it merely applies the corresponding data to the line LI, and the controller 13 processes or ignores the command depending on whether or not it is ready. In other words, when the controller 13 is not actually processing commands, it listens permanently to the line LI so as to process any new commands that may appear thereon. Otherwise it merely ignores a command. Advantageously, each command sent by the modem 12 to the controller 13 is terminated by an end character such as carriage return ( <CR> ), which is necessary to cause the command to be executed. According to another aspect of the invention, the resident programs in the modem and in the controller circuit are designed so that the modem program can send a status or state request command to the controller program, as described in detail below, after which it waits for a reply in the form of a message in a predetermined format including a string of characters that is representative of the state of the control circuit and of the transmitter/receiver. This string of characters is terminated by <CR>. As also described below, various types of status can be requested. The signals interchanged between the modem 12 and the controller 13 are as follows: a) logic signals: Txo: data output from modem; Rxi: data input to modem; auxiliary I/O: used for general purpose input/output; PowerOn: a pulse signal for "waking up" the controller circuit and the transmitter/receiver circuit (switch on); Ring; Ring_Txa_Sel: a control signal for an analog switch that selectively applies to the analog input terminal of the modem either a ring digital signal or an analog signal. As mentioned, transmission over the serial link is asynchronous, no clock signal is conveyed. The clock frequencies of the modem microcontroller and of the controller circuit microcontroller are merely set to values that are appropriate for clocking signals suitably. Preferably, the selected data format comprises a start bit at a low logic level, eight data bits, and a stop bit at a high logic level. The 8-bit data is transmitted beginning with the least significant bit. b) analog signals: Txal, Txa2: positive and negative terminals for analog data output from the modem in the form of differential signals; and Rxal, Rxa2: positive and negative terminals for analog data input to the modem in the form of differential signals. There follows a detailed description of the format of the commands transmitted to the controller circuit 13 by the modem 12 in the event that a telephone call by radio has been selected (the way in which such a selection is made is described above) . Preferably, commands are used taken from a set having the following format: AT"command<CR> AT is a prefix, indicating that this is a command, and it is identical to the prefix of a standard set of predefined commands for a conventional modem connected to the telephone network by a cord; " is a special character serving to distinguish between a conventional "AT" command of the kind mentioned above, and a specific command generated by the modem and applied by the modem to the controller circuit; and <CR> is the required "carriage return" character. Depending on the size of the input buffer register of the controller circuit, the command proper may be of greater or shorter length. Should a longer command be required, then two commands as defined above are sent in succession, and the microcontroller of said controller circuit concatenates the commands proper. Commands 1) As mentioned above, a most important command in the set of commands from the modem 12 to the controller 13 is a keypad emulation command. This command may have the following format: AT"KPklk2...kn<CR> kl to kn designate ASCII format characters corresponding to the keys of a CT2 standard radiotelephone keypad. For example, the correspondence between a simulated key and an ASCII code may be as follows: 0 = $30 1 = $31 2 = $32 3 = $33 4 = $34 5 = $35 6 = $36 7 = $37 8 - $38 9 = $39 * = $2A # = $23 0 = $4F (On) C = $43 (Clear) R = $52 (Redial) S = $53 (Shift) M - $4D (Memory) P = $50 (Phone) U = $55 (volume Up) D = $44 (volume Down) 2 12 T = $54 ( muTe ) F = $46 (Flap, i.e. an overall on/off command corresponding to the flap of a foldable radiotelephone being opened or closed). The values given above are in hexadecimal format. 2) A hang-up command for disconnecting an established link may have the following format: AT"HO<CR> When transmission is in radio mode, this command is applied to the circuit 13 by the modem 12 when the modem itself receives a standard hang-up command from the computer. On receiving this command, the controller circuit 13 causes a "FULL_RELEASE" instruction to be sent to the central station, said instruction being taken from the CAI standard. This should cause the link to be disconnected immediately by the base. However, under certain conditions, the base station may desire to prolong the link. To see whether this situation has arisen, the modem may, as described in detail below, send a status request following the hang-up command, and it may be programmed to respond (e.g. by sending a message to the user) as a function of the status it actually receives. As will be seen below, a power-off command may also be used to disconnect the link. 3) A command for starting access to the link may be used to establish a radio link. The circuit 13, 14 then attempts to establish a link in default mode (public mode or private mode) and in a default "slot" (for more details about these concepts, reference should be made to the above- mentioned CT2 standard - in particular, the term "slot" is used herein to designate a particular location in a table of parameters). That said, it is explained below that the user of the computer has the option of programming a particular slot and/or mode and of conserving such parameters in memory. This command is sent by the modem 12 to the control circuit 13 when transmission is to be performed in radio mode and the modem receives a standard off- hook command from the computer. As for other commands, it is the microcontroller that generates the appropriate AT " type command as a function of the standard AT command received. Provision may be made for establishing two types of link, namely one type for data in voice band, and another type for voice communication. In the first case, the mute function in the control circuit 13 is disallowed, whereas in the second case, it is allowed. For example, 5 seconds after sending such a command to the circuit 13, the modem may send a status request to find out whether a link has, in fact, been established. It may be observed at this point that the modem can determine the identifier of the active slot used from the status information provided by the circuit 13. For example, the command for establishing a voice band data link may be as follows: AT"H1<CR> The command for establishing a direct voice link may be as follows, for example: AT " H2<CR> At this point, it may be observed that if the link is lost during a call, then the circuits 13 and 14 will observe a loss of carrier. However, the circuit 13 has no way of informing the modem. Under such circumstances, it is advantageous to provide for the circuits 13 and 14 to attempt to reestablish the link using the CAI specification, and to inform the modem by means of the status message whenever the modem sends a corresponding status request. 4) An power-off command may be provided to enable the controller circuit 13 and the transmitter/receiver circuit 14 to be powered down. Under such circumstances, and in a manner as defined in the CT2 standard, the active processes and the active links are terminated and configuration data is stored in the programmable memory of the circuit 13, e.g. EEPROM type memory. After being powered down, the circuits 13 and 14 can no longer accept incoming calls, nor can they ask for a link to be established. Preferably, after an power-off command has been sent, the modem waits for a predetermined time-out, e.g. 3 seconds, before switching off the power to the circuits 13 and 14. This enables the circuit 13 to perform its power-down sequence in full. It may be observed, that when powered-down, the circuit 13 can no longer send its status to the modem. This power-off command is particularly appropriate for a portable computer that is battery powered, since it enables battery power to be saved whenever there is no request for a radiotelephone call. The format of power-off command may be as follows: AT"P0<CR> 5) As a corollary, a power-on command is also provided for the circuits 13 and 14. This command enables power to be applied to said circuits, and it also serves to "warm start" or reinitialize the circuits 13 and 14. When the circuit 13 receives a power-on command, it reinitializes itself, and in particular it loses its current configuration. It is the configuration previously saved by the user in the EEPROM of the circuit 13 which is automatically recalled. At this point, it may be observed that the behavior of the circuit 13 as described above is the same if the circuits 13 and 14 are switched on merely by applying power to them. The format of this command may be as follows: AT ~ P1<CR> 6) Provision is also advantageously made for a save settings command which is sent by the modem 12 to the circuit 13 requesting it to save its current settings (or configuration) in its non-volatile EEPROM. In this way, if there should be a drop in the power supply voltage, then the circuit 13 would still be in a position to return to its preceding configuration on receiving the above-described power-on command. This characteristic is particularly useful when two or more "associations" are open in the modem 12 of a computer of the model mentioned above. Thus, when an open association desires to conserve the parameter settings of the circuits 13 and 14, the modem is programmed so as to send a save settings command to the circuit 13 instead of a power-off command AT"P0<CR>, since it is necessary to avoid interrupting the radio link which may still be in use by other associations. The format of the command may be the following: AT"P2<CR> 7) A command may be provided for switching the gircuits 13 and 14 to private mode. On receiving this command, the circuit 13 switches to private mode and uses the default private slot as the active slot. As described below, it is possible to change slot by sending a slot selection command. When setting up a link, a slot identifier ("LID") is used to designate the active slot for a link that makes contact with the private base station. The circuits 13 and 14 will remain in private mode until a switch to public mode command (see above) is received. The format of the private mode command may be as follows: AT"M0<CR> 5 8) Similarly, a command having the format AT"M1<CR>, for example, is provided for switching the circuits 13 and 14 to public mode. This is done in substantially the same manner to that described above for switching to private mode, except that it now 10 switches to public mode. Similarly, the circuits 13 and 14 remain in public mode until they next receive a private mode command AT " M0<CR>. 9) A command is also provided enabling the 15 circuits 13 and 14 to register with a private base. To do this, the circuits 13 and 14 must have a private slot available. It is the modem that determines whether such a slot is available. Once the circuit 13 has received such a command, 20 it returns a link identifier value in the range $0401 to $FFF3 to the modem if the slot is presently occupied, and equal to $FFFF if the slot is available. When there is no available private slot, then it is up to the user to make one available, otherwise , 25 registration will not be possible. At this point, it will be observed that, in order to be able to operate, the registration process triggers the establishment of a link since registration requires such a link with the private base. 30 The format of this private registration, may be the following: AT"RKCR> To validate the registration, the modem sends another command to the circuit 13, e.g. of the format: 35 AT"KP#<CR> 10) To deregister from a private base, the user must provide the circuit 13 (via the modem) with a command on an occupied slot which contains the link identifier of the base from which deregistration is desired. The deregistration process takes place after previously establishing a link with the base. The format of this command may be as follows: AT " RO<CR> 11) It is also possible to provide a public registration command. Unlike private registration, public registration does not require the existence of an available public slot. Initiation of public registration on a slot that is already occupied will overwrite the existing registration. Nevertheless, it is up to the modem 12 to determine whether a slot can be used or not. The circuit 13 returns a link identifier value lying in the range $0000 to $03EF if the slot is presently occupied, and a value $FFFF if the slot is available. The format of this command may be as follows: AT"KPS4M<CR> When registering with a "Telepoint" server, the modem 12 must transmit certain blocks of data to the server via the circuits 13 and 14. These blocks may be transmitted by means of a command having the following format: AT"KPxx...x<CR> where xx...x are the data block. The program resident in the circuit 13 increments a block number to be received each time a block has been received correctly. An OK message may be sent via the modem 12 to the application in operation in the computer once all of the blocks have been transmitted correctly, or else an error message is sent if a problem has occurred. At this point it may be observed that seen from the application, the same process takes place except insofar as the data blocks are delivered to the circuit 13 via the modem by using a special command, e.g. AT~Bxx...x<CR>. When such a command is sent to the circuit 13 by the modem, the modem knows that it must wait for an acknowledgment from the circuit 13, which in this case merely indicates the number of the next block to be processed. It may be observed that in order to cancel the process of transmitting blocks that relate to Telepoint registration, the application may request the modem to transmit a command AT " KP#<CR>. This cancels the process from the start. 12) Provision may also be made for a simplified "OTAR" public registration command. In short, this is a registration process that takes place during radio transmission and which is performed after a link has been established between the computer and the public telephone network. This simplified registration has the advantage of reducing the quantity of data to be interchanged. The format of this command may be as follows: AT"KPS4M*<CR> As in the preceding case, a suitable user interface must be provided for entering the data required for registration, with said data being transmitted, as before, by commands of the AT'Bxx...x<CR> type. An application is advantageously designed to enable the user to select between normal public Registration and simplified registration. 13) It is also possible to provide a local deregistration command, for use both in public mode and in private mode. This command implies that the slot and the appropriate mode have previously been selected by commands that are explained below. In the present example, the format of this command is: AT"KPS4MC<CR> Since this procedure is purely local, i.e. it does not require a link to be established, it may be considered as a slot delete command for releasing the slot. However, when the mode is public mode, the user must understand that access to the public network will thereafter be denied, and that the server must be re- contacted in order to perform a new registration procedure. 14) A localization command may be provided for enabling the computer to receive calls. This can be done in public mode only. Before sending this command to the circuit 13, a link must have been established between the computer and a public base. The format of this command may be as follows: AT'L1<CR> A problem specific to this command is the presence of a voice message coming from the base. A particularly advantageous solution consists in detecting electrical energy to determine the instant at which such a message comes to an end. The modem can then send a command to the circuit 13 such as: AT"KPxx<CR> after the end of the voice message, where xx specifies the duration of localization, in ASCII format and in predetermined time units. This duration is preferably determined once and for all. , It should be observed here that the computer is designed previously to recognize the frequency of the polling sequence from the "Page Information" message that is conventionally returned by the base. 15) A delocalization command may also be provided to prevent calls being received. This command can be performed in public mode only. A link with a public base must previously have been established. In this example, the delocalization command may be as follows: AT " L0 <CR> 16) As mentioned above, a slot selection command is provided for selecting a particular slot in public or private mode. For example, the computer may have eight private slots and four public slots available to it. This command may be as follows: AT"KPS4<CR> where n designates the number of the slot and lies in the range 1 to 8 for private mode and 1 to 4 for public mode. 17) A command may also be provided for retrieving the electronic serial number (ESN) from the module 13, 14. In the present example, this command may be: AT~E0<CR> After sending this command, the modem puts itself in receive mode and waits to receive the ESN number in asynchronous mode via the serial interface. It will be observed that since the serial number may be longer than the status data, a special format may need to be created, e.g.: AT'dl...dl2<CR> in which dl to dl2 are the 12 digits of the serial number. 18) A number can be dialled only after the computer has waited for a link to be established. A keypress emulation command is then applied to the circuit 13. When dialing in public mode, the string of digits must be terminated with a "#". Dialing thus takes place as follows: AT"KPabcdef...<CR> in private mode; or AT"KPabcdef...#<CR> in public mode; where abcdef... designates the number to be dialed. Mention is made above on several occasions of the circuit 13 supplying status information to the modem, in particular for the purpose of providing information on how various processes that have been started are proceeding. As mentioned above, status is sent only after a status request, i.e. by sending a command AT"S<CR> and waiting for a reply. Several different statuses can be envisaged. 1) Standard status We begin by giving an example below of the information which the modem 12 requires to enable it to handle its connections with the controller circuit 13 properly. In the present example, this information occupies two general status bytes. Specific information may follow these two bytes. Byte 1 Bit 7 (system status) 0: the circuits 13 and 14 are busy, and part of the status information may be invalid; 1: the circuits 13 and 14 are ready and the status is valid. Bits 5 and 6 (link) 00: no link present; 01: link present; 10: link being established or reestablished; 11: ringing (this is a second way of indicating that ringing is taking place - see below for ringing simulation). Bit 4 (signal strength) 0: weak signal; 1: strong signal. Bit 3 (localization/delocalization) 0: not localized; 1: localization active. Bits 2 and 1 (registration status) 00: bad block; 01: good block; 10: bad registration; 11: good registration. Bit 0 (lock status) 0: unlocked; 1: locked. It can be seen here that the circuits 13, 14 may be locked out (operation not allowed) or unlocked. Commands of the type AT"KP...<CR> are used to switch the circuits from one state to the other. Byte 2 Bit 7 Not used. Bit 6 (public mode flag) 0: not valid; 1: public mode active. Bit 5 (private mode flag) 0: not valid; 1: private mode active. Bit 4 (unknown mode flag) 0: not valid; 1: unknown mode. Bits 3-0 (slot number) A digit in hexadecimal format. The following data follows the above main two bytes: Link identifier Four digits in ASCII format (four bytes). Registration block number One digit in ASCII format (one byte). All of this information is transmitted each time the modem 12 makes a status request. The status thus comprises a total of seven bytes and in the present case its format is as follows: AT * <bytel><byte2xlinkID><blockNo.><CR> 2) Extended status This second status format may be used, in particular, for enabling the computer to emulate a portable telephone having a keypad and a display. This extended status is transmitted to the modem 12 by the circuit 13 after it has received an extended status request command which may be as follows: AT"S1<CR>. Keypress simulations are sent to the controller circuit 13 by above-mentioned commands AT"KP... <CR> . Extended status information is used to obtain from the circuit 13 the data required for making the computer screen emulate the display conventionally provided by a portable radiotelephone (mainly in the form of text and icons) . The description below relates to an example in which the circuits 13 and 14 are of the type used in a portable radiotelephone of the type capable of displaying eight different symbols or icons, namely: a "busy" indicator; a "public" indicator; a "private" indicator; a "on" indicator; a "shift" indicator; a "locked" indicator; a "scroll" indicator; a "ringing" indicator. Each of the above symbols can take up three states: off, on, or blinking. Each symbol may be described by means of two bits: Bit 1 1: blinking; 0: not blinking. Bit 2 1: on; 0: off. The states of the eight symbols as determined by the circuit 13 can therefore be encoded on two bytes. When the controller circuit 13 controls a larger number of symbols, one or more additional bytes may be provided. In addition, assuming that the controller 13 is capable of controlling a 12-character display, these 12 characters (e.g. in ASCII format) may be added on after the two bytes of symbols as defined above. These bytes comprising symbols and characters are transmitted in an extended status message having the same format as the standard status message, i.e. they are preceded by AT * and followed by <CR>. 3) Status as seen by the application To enable an application to obtain the status of the circuits 13 and 14 via the modem 12, provision may also be made for special commands: AT"S?<CR> and AT"S1?<CR> which correspond respectively to the modem's standard status request and to the modem's extended status request. The status information received by the modem is then transmitted to the application in hexadecimal format. Ringing detection As mentioned above, the hardware of the analog signal interface between the modem 12 and the controller circuit 13 comprises two analog transmit signal channels and two analog receive signal channels. This thus constitutes a 4-wire interface. When the modem operates with direct connection to the public telephone network by cord, it is in 2-wire mode. Ringing information arrives on what corresponds to analog signal reception in 4-wire mode. In order to conserve ringing detection as already incorporated in the program resident in the modem, the controller circuit 13 is designed to emulate a ringing signal, written ERING, by applying modulation to a special conductor. A logic inverter is provided for selectively applying said emulated signal to the analog receive input of the modem. The corresponding circuit is shown diagrammatically in Figure 3. The analog inverter 100 has a control input on which it receives a ringing/analog transmission select signal written Ring_Txa_Sel. The input terminal A of the inverter 100 is connected to the above-mentioned special conductor. The input terminal B of said inverter is connected to the output of a 2-input differential amplifier 110 which has the positive and negative analog receive signals RXA1 and RXA2 respectively applied thereto. The output from the inverter 100 is applied to the analog receive input RXA of the modem. In this way, when the circuits 13 and 14 receive a call from the base, ringing is simulated for the modem 12 which is then in 2-wire mode. It is only once line establishment has terminated that the modem switches to 4-wire mode. Thus, to detect ringing, the resident program in the modem is not altered to accommodate the circuits 13 and 14. Figure 4 shows the hardware of the interface in 4- wire mode and in 2-wire mode. Reference 12b at the bottom of Figure 4 designates the telephone line interface. Naturally, the present invention is not limited to the embodiment described and shown, and the person skilled in the art will be able to make variations and modifications thereto that come within the spirit of the invention. There follows a detailed appendix with examples of the various commands implemented in the present invention. 0/ Issues & History History 1.0a4 - Dec 1: • Switch from PowerBop to PowerBop II . Changed all th hardware interface specification, including the timings . 1.0a4- 1.0a5 • Added Change Bars to all the paragraph which have bee changed. • Changed the description of Commands and Status exchange between the CT2 Module and the Modem. • Added the command to retreive the Electronic Seria Number (AT Λ E0). • Added Description of the Extended Status (AT Λ S1) fo keyboard emulation. • Added the AT Λ P2 command to force the CT2 module to sav the current settings programmed by the modem, but withou turning itself off. • Added the AT A H2 command to make the difference betwee voiceband data mode links, and straight voice links. Remaining Issues • Management of Vocal Messages 1i • Management of Display Messages ! 1 • What happens if you want to deregister from a bas station and your too far from it. Does that comman requires a transaction between the Terminal and the Bas station ? • Having the possibility to have the signal strength durin the connection. • Change AT Λ S into AT A S0. • Add in the format of the status, a byte to identify th type of status. A different byte for the 2 different statu (SO, and SI) and for the Electronic serial numbe retreival. 1/ General Description PowerBop is a CT2 modem, based on the Apple PowerBoo Express modem and the Motorola Silverlink CT2 telephon handset. This modem can take place in PowerBooks 160,165c 180,180c. 2/ General Architecture The way this modem is implemented is the following one: • The normal PSTN modem will control the Silverlin controller board. • The Silverlink controller board will control th Silverlink tranceiver board. In that way the entire device will be able to make mode connections over the air using the CT2 protocol. The mode is responsible of doing the modulation-demodulation proces and all the high level protocols (like the T30 protocol, MNP and V42 data protocols). The CT2 controller i responsible of the link access and link management. In order to have the modem control the CT2 radio interface we have defined a set of commands and status. Basically these commands have been defined to emulate th "Key Presses" of the Silverlink phone Set, and allow th modem operate with CT2 controller board like a huma operator would operate with the Silverlink Phone Set. W defined a standard Key Press" command, plus some special commands to perform some of the basic functions. 3/ Hardware Interface The hardware interface between the modem and the CT2 device, is based on a Motorola SCI, working in Asynchronous mode only, with 1 extra wire which can be used for general purpose Input/Output. 3.1/ Description The logic interface is shown in Figure 2 . Commands: From Modem to CT2 device. Whenever the modem wants to send a command to the CT2 device, it just starts sending the data out, using the SCI asynchronously. This is based on the fact that when the CT2 module is free from processing special AT commands, it should be ready to receive commands at any time. If the CT2 device has not completed execution of the previous command it will ignore the current command, and continue processing. If the CT2 device is available it will accept data from the SCI Tx line. If the command is not terminated by a <CR> then it will not be processed. On the next Send Command cycle the unterminated command will be disposed of and the new command accepted. In this way the CT2 device will provide facilities to correct erronous command transfers and lockups. Status: From CT2 device to Modem. Whenever the modem wants to have a report on the progress of the current process, it has to send the special command "AT Λ S" on the SCI in asynchronous mode to the CT2 module. Just after sending that command the modem will setup itself in Receive mode to recover the data (status) sent by the CT2 module on the SCI in asynchronous mode. The status needs to be always terminated with a <CR> character. The command AT Λ S will request the standard status as defined at the end of this document. To extend the format of the data which can be retreived by the modem from the CT2 module, extra AT Λ Sn can be defined where n can take all the values from 1 to oo 3.2/ Electrical interface & Timings The signals exchanged between the Modem and the CT2 device are described above. Concerning the Logic signals we have: Txo (DataOut from the Modem) Rxi (Dataln for the Modem) ExtraI/0(Used for general purpose Input/Output) PowerOn (Pulse to stimulate the PowerOn of the handset) Ring Ring_Txa_Sel (Selection of the Ring digital signal or the Txa analog signal => Used to select the analog switch) . All these I/O lines are terminated with PullDown resistors on the CT2 device side. The baud rate used by the SCI on the modem side is 9.765 KHz (due to the ^controller clock of 5 MHz), and on the CT2 side 9.6 KHz. The deviation is low enough to be compensated by the SCI, knowing that the transfers are composed by a small amount of characters. The asynchronous data format is 1 stop bit, 1 start bit and 8 data bits. The levels for these logic signals are: VIH = 2.72 V to 3.2V VIL = 0 V to 0.85V These levels are specified for a CT2 device Power Supply of 4.5V. Concerning the Analog signals we have: Txal (Analog Data Out from the Modem - positive differential signal) Txa2 (Analog Data Out from the Modem-negative differential signal) Rxal (Analog Data In for the Modem - positive differential signal) Rxa2 (Analog Data In for the Modem- negative differential signal) Concerning the power Signals we have: + 4.5V GND • Write/ Read Cvcle Tάjming Diagram: see figure 5 • Orders of Bits All the characters transmitted on the SCI will be in the following order: First bit transmitted is LSB. 4/ Commands 4.1 /Command Format To assure synchronization between the different devices which are receiving and interpreting the commands , this command set is based on a pseudo AT command set . Following the AT character sequence , a special character is added indicating that the command is a PowerBop low level AT command. To avoid confusion with the standard AT Command set , the character """ has been chosen as the special PowerBop AT character. The general format of the AT PowerBop command will look like: T Λ Command CR All the commands end by a CR. Maximum Command Length: The command part of the AT sequence is limited to 10 characters due to the limited buffer on the CT2 device. The "KP" command is the only command which may need to exceed that limit (because of long dial strings). In this case, the modem will need to break the keypresses into 2 "Kp" commands and send them separately over the serial interface. The CT2 device will concatenate these keypresses and handle them as one series of keypresses. 4.2/ "Key Press" Command The "Key Press" Command is the Basic command which allows the modem to operate the CT2 controller board like an operator would use the keyboard of the Silverlink. This kind of command is especially used to dial the number. The ID of this command is KP , and it is followed by the ASCII codes of the keys to be pressed. kl Jt2 kn CR The characters accepted are: 0 - Ascii 530 8- Ascii S38 M(emory)- Ascii S4D 1 - Ascii S31 9- Ascii S39 P(hone) - Ascii S50 2 - Ascii S32 *- Ascii S2A U(p Volume)- Ascii S55 3 - Ascii S33 # - Ascii S23 D(own Volume)- Ascii S44 4 - Ascii S34 O(n) - Ascii S4F T(Mute) - Ascii 54 5 - Ascii S35 C(lear)-Ascii S43 F(lap) - Ascii S46 6- Ascii S36 R(edial)-Ascii S52 7- Ascii S37 S(hift)- Ascii S53 Note: It is possible to send specific commands to the CT2 device by concatenating specific keypresses in a "KP" command. This feature provides complete access to all the commands which are present in a Siverlink handset. Where specific commands are listed below in this document they should be used rather than concatenating "KP" commands. 4.3/ Hang Up Link Command The Hangup command is used to break a link already established. It corresponds to going On hook for a Modem on the PSTN (Public Switched Telephone Network) . On reception of that command the CT2 device will transmit a CAI FULL_RELEASE to the base station. Normally this will cause immediate termination of the link by the base, but under certain circumstances the base may wish to extend the link. To determine that situation the modem will check the status and will react appropriately. The ID of this command is HO A IT I Λ IHIOICR In the case the system wants to terminate a link immediately (yet gracefully) the "Power Off command" AT Λ P0 has to be used (see below) . 4.4/ Initiate Link Access Command The Initiate Link Access command is used to try to establish a radio link. It will be attempted on the default mode and slot (either Public or Private), unless the user has selected an alternate slot or mode since power up. It corresponds to going Off hook for a Modem on the PSTN (Public Switched Telephone Network). There are 2 different types of link establishment, 1 for voiceband data (HI) and 1 for straight voice (H2). In straight voice mode, muting will be allowed on the CT2 module whereas in voiceband data mode it will not. The attempt to get a link will last 5s, after that the modem will know if the link access was successful by reading the status given by the CT2 device. Within the same information, the modem will get the Identifier of the active slot which is used. The ID of the command for establishing a voiceband data link is HI A T H 1 CR Note: If during a connection there is a loss of the link, the PowerBop system will detect the drop of the carrier. However the CT2 device will not issue a hangup command since there's no link to signal this. Rather the CT2 device will attempt to re-establish the link per the CAI specification requirements and will report this activity in the status. The ID of the command for establishing a straight voice link is H2 A m 1 Λ H 1 2 CR 4.5/ Power Off Command The PowerOff command is used to turn off the CT2 device (Controller board and tranceiver board). Active processes and active links are gracefully terminated and configuration data is stored into the CT2 EEPROM. In that mode the CT2 device will then not be able to accept incoming calls, and will not be able to issue any link access. After issuing completely that command, the modem will have to wait 3s before removing the power source in order to let the CT2 device perform completely its Power Off sequence. Furthermore, no more status will be at that point available. The ID of this com-mand is P0 A T P 0 I CR Note: When the PowerBop system wants to keep the current configuration in Non Volatile memory, it can issue the AT A P0 command. When the System is turned on again, it will start with the saved configuration. 4.6/ Power On Command The PowerOn command is used as a Warm boot command or as a Reset command to a presently powered CT2 device. Issuing that command will cause the CT2 device to reinitialize itself and lose all current configuration. Current configuration will not be saved in permanent memory, and on restart the last saved configuration will be recalled from the permanent memory (EE PROM). To do a real Power On, the powerBook will just have to supply the voltage to the CT2 device. The ID of this command is PI A T CR 4.7/ Save Settings Command The SaveSettings command is used by the modem to tell the CT2 Radio module to store the configuration data into its EEPROM. in that way if a drop of the power supply occurs, the CT2 module will always wake up in the programmed mode. Note : This is especially used in the case several associations are opened within the Express Modem. When one of the association opened is setting the parameters of the CT2 module it cannot issue the AT Λ P0 command because it must not turn the Radio module off (which could be used by the other associations. The ID of this command is P2 A T P 2 CR 4 . 8 / Private Mode Command The Private Mode Command, is used to switch the CT2 device in private mode. On reception of this command, the CT2 device will switch its mode to private and use the default private slot for its active slot. The active slot may b changed by issuing the Slot selection command. Link initiations will use the LID (Identifier) from the activ slot to contact the private base. After executing that command, the system will remain i Private mode until the command "Ml" described below is executed. The ID of this command is MO A T M 0 CR 4.9/ Public Mode Command The Public Mode Command, is used to switch the CT2 device in public mode. On reception of this command, the CT2 device will switch its mode to Public and use the default public slot for its active slot. The active slot may be changed by issuing the Slot selection command. Link initiations will use the LID (Identifier) from the activ slot to contact the public base. After executing that command, the system will remain in Public mode until the command "MO" described above is executed. The ID of this command is Ml A T M 1 CR 4.10/ Private Registration Command To be able to register to a Private base by using this command, the CT2 device needs to have a private empty slot. It is the responsability of the modem (user) to determine if a slot is available or not. The CT2 device will return a LID) value $0401 to $FFFE if the slot is presently occupied, and SFFFF if the slot is empty. In the case there are no private empty slots available, the user will have to liberate one, or will not be able to register. The registration initiates in the same time a link access, as it is an over the air process. The ID of this command is Rl A T R 1 CR After that command is executed by the CT2 module, a link is established between the PowerBop system and the private base. To validate the registration action the AT Λ KP# command has to be issued. We get the following sequence: AT Λ R1 <CR> -> <- Check Link established AT Λ KP#<CR> -> <- Wait for Registration OK and terminate the registration action 4.11/ Private Deregistration Command To deregister from a private base, the user has to issue that command on the non empty slot which contains the LID of the base to be deregistered. in that case the deregistration occurs over the air. The ID of this command is RO A T R 0 CR 4.12/ Public (Telepoint) Registration Command Unlike Private registration the CT2 device does not absolutely need to have a public empty slot for this kind of registration. Initiation of public registration on an already busy slot will overwrite the existing registration. It is however the responsability of the modem (user) to determine if a slot can be used or not. The CT2 device will return a LID value $0000 to $03EF if the slot is presently occupied, and $FFFF if the slot is empty. The ID of this command is KPS4M A T K P s 4 M CR When registering to a Telepoint Service Provider, the PowerBop system has to enter several blocks of data. Let's describe the way the blocks are entered into the system. AT Λ KPS4M<CR> -> <- Check Block # to be entered and forward to Application AT A KPXXXXX<CR> -> < - Increment blok # to be entered i f eveything OK AT Λ KPXXXX<CR> -> ( corresponding to the last block ) <- send OK, or ERROR to Application ( Indicates registration result ) Application interface (Caution) On the application side, the same process as described below will occur, except that the blocks of data will be passed to the modem using a special command (AT Λ B). In this way the modem knows that it has to wait for the CT2 device acknowledgement, and displays only in that case the Block number which has to be processed next. We will have the following sequence: AT Λ KPS4M<CR -> <- BO AT Λ BXXXXX<CR> -> Bl (if data is correct or BO if not) AT Λ Bxxxx<CR> -> ( corresponding to the last block) <-- OK, or ERROR (indicates registration result) To escape correctly in the middle of the process of exchanging blocks, the Application will have to send a AT Λ KP# command. This command will cancel the Telepoint registration and will cause the CT2 module to be back in idle mode. Note: If an error occurs on the last block, it will break the complete registration, and it will not be possible to reenter the block again. In this case the user will have to go through the entire registration process again. 4.13/ OTAR Registration Command OTAR Public registration has been introduced later, and has been provided to simplify the registration process. It is an over the air registration, which is done after a link is established between the PowerBop system and the public network. Much less data is required to be exchanged between the system and the Public network. The ID of this command is KPS4M* K P S 4 M * CR The same kind of user (Application) interface will be provided to enter the data needed for the registration, and the AT Λ B command has to be used. Generally only 1 block is needed for that type of registration. ****** Warning ****** In order to let the user choose between Manual public registration, and OTAR registration (which depends on the network), the User Interface will provide an OTAR/Manual selector, and will have a Registration activator. Depending on the registration chosen, the Application will send to the modem the following commands: • AT Λ KPS4M* for OTAR • AT"KPS4M and then will have to send the Blocks-of data. ****** Warning ****** 4.14/ Terminal DeRegistration Command This deRegistration command is valid only locally (without accessing any base station) to the PowerBop system. It can be done both in Private mode and in Public mode. Prior to this local deregistration the right slot and the right mode (Public or private) have to be selected - See command below. The ID of this command is KPS4MC As the Terminal deregistration is a local process (no link needs to be established), we can see as it is a Slot eraser command, which makes the Slot selected free again. However in the case of Public mode the user needs to be aware that he will not be any more able to connect to the Public network, and that he will need to contact the Service provider to do the registration process again. 4.15/ Localization Command on a Public Base The Localization command is used to let the PowerBop system receive incoming calls. It can be done only in Public mode. Prior to issue that command, a link between the PowerBop system and a Public base has to be setup . The ID of this command is LI (Corresponding to KPS8 of th Handset ) A | T L 1 CR issue: The Page Info message has to be handled by the PowerBop system. To avoid having a too complex user interface (Through Vocal messages), the duration of the Localization will be forced to a predetermined time. The modem or the CT2 device will perform an Energy detection to know when the Vocal message is finished, and then will know that it can send the Duration to the Public base. However the PowerBop system will have to recover the frequency of the Polling sequence the Public base will return in the Page Info message. Let's describe the sequence of the commands: AT Λ L1 -> <- OK Indicates link is established AT Λ KPxx -> Corresponds to the duration of the Localization <- OK xx is the duration given to the Public network, and its format is a serie of ASCII digits. Depending on the network, the unit can be different (some in seconds, other in Minutes, . ). 4.16/ DeLocalization Command on a Public Base The DeLocalization command is used to let the PowerBop stop receiving incoming calls. It can be done only in Public mode. Prior to issue that command, a link between the PowerBop system and a Public base has to be set up. The ID of this command is L0 (Corresponding also to KPS8 of the Handset) 4.17/ Slot Selection Command This Command is used to select a specific slot in either private mode or public mode. The PowerBop system has 8 private slots and 8 public slots. The ID of this command is KPS4n n range is from 1 to 8 in Private mode n range is from 1 to 4 in Public mode 4.18/ ESN Retrieval This command is used by the Modem to retrieve the Electronic Serial Number of the CT2 module to which it is connected. The ID of this command is EO A T E 0 CR After sending that command the modem will setup itself in Receive mode, and will expect the data composing the ESN to arrive through the SCI in asynchronous format. Since that Data which needs to be retreived by the modem does not fit the standard Status format, we need to define a new format of data to take care of this case. The ESN is composed of 12 digits, which are just going to be appende to the AT status identifier, and this will look like: A|TI" Idigl|dig2|dig31dig4|dig51 |dig51dig61dig71digδ|dig91eiiglO|digll|digl2|CR 4.19/ Dialing a Phone Number To dial a phone number, the PowerBop system will first hav to wait, that a link has been established. After that, the Key Press command is used to pass to the CT2 device th Dial String. The dial string has to contain a "#" character at the end, in the case the dialing occurs in Public mode. Example: Here is the serie of commands to issue to dial phone number AT A H1 Wait for status OK on link access "AT Λ KP" dial String" in Private mode "AT Λ KP" dial String#" in Public mode 5/ Status The Status is used by the CT2 device to report som information to the modem (which controls all the PowerBo device) about the progress of the different processes engaged. It is the modem which will always ask for the statu information (by sending the AT Λ S command, and this ensure synchronization between the 2 devices. 5.1/ Standard Status (AT Λ S 5.1.1/ List of Status Information Below is the list of the different kind of information, the modem will need to be able to handle the CT2 connection correctly. This information is distributed within 2 bytes of general status followed by specific information. For every information reported in the status, we list also the different values it can take. Status Byte 1 Bit 7: CT2 System Status 0 -> CT2 device busy and part of status may be invalid I -> CT2 device ready and status is valid Bits 6 & 5: Link 00 -> No link present 01 -> Link present 10 -> Link (re)establishing II -> ringing(and alternate ring indication via status) Bit 4: Signal Strength 0 -> Weak signal 1 -> Strong signal Bit 3: Localization/DeLocalization: 0 -> Not localized 1 -> Localization active SUBSTITUTE SHEET (RULE 26 Bit 2 & 1: Registration Status 00 -> Bad Block 01 -> Good Block 10 -> Bad registration 11 -> Good registration Bit 0: Lock Status 0 -> Unlocked 1 -> Locked To specifically lock or unlock the CT2 device in order to block its functionning, the modem will use the AT Λ KP command with the right keys included. Status Byte 2 Bit 7: Flag not available => never valid Bit 6: Public mode indication 0 -> Not valid 1 -> Public mode Bit 5: Private mode indication 0 -> Not valid 1 -> Private mode Bit 4 : Unknown mode indication 0 -> Not valid 1 -> Unknown mode bit 3,2,1 & 0: Slot number -> Format is 1 digit in hex format. Status LID (4 bytes) 4 digits in Ascii format Registration Block number (1 Byte) 1 digit in Ascii format. All the information is retreived each time the modem wants to know the status. All the bits are grouped in 2 bytes, where some of the bits are reserved for future use. The rest of the information will be put in bytes for every digit listed above. 5.1.2/ S atus Format The Status is composed in total of 7 bytes plus the AT characters for synchronization, and a special character ( ' ) different from the previous one ( Λ ), to differentiate Commands and Status. AjTj *" IStatus BytelIStatus Byte2|LID1 |LID2 |LID3|LID4 |Blk#|CR The Status byte 1 includes the first part of all the bits previously described in the following order: CT2Ready I Linkl I Link2 I Signal I Localization I Registration! I Registration! I Lock The Status byte 2 includes the second part of all the bits previously described in the following order: N.U I PublicMode I PrivateMode I UnknownMode I Slot#l I Slot#2 i Slot#3 I Slot#4 To get an idea of the status retreival by the modem, we will have the following sequence of commands and responses: AT Λ S<CR> -> <- AT ^ 804131323334000D means the CT2 module is ready, it is in public mode, and the slot selected is the first one. The LID of the slot selected is 1234, and the block number is 0. 5.2/ Extended Status (AT Λ S1) This second status format will be used to perform on the Macintosh side the Handset Keyboard emulation. The system will handle that feature by using the AT Λ KP command for sending any Key presses informations, and will use the status described below to get the data which needs to be displayed on the Handset emulator. The CPU will need to simulate the different icons available on the handset display plus the different strings which are normally displayed during the operation. 5.2.1/ Icons We have 7 different icons, 1 for BUSY indication, 1 for PUBLIC indication, 1 for PRIVATE indication, 1 for POWER indication, 1 for SHIFT indication, 1 for LOCKED indication, 1 for SCROLL indication and 1 for RINGER indication. Each icon has 3 different states: On, Off, or Blinking. To encode each icon, 2 bits are needed which makes a total of 14 bits. However to keep the handset compatibility (which is forecasting extra icons for the future), 3 bytes in total are used. In figure 6 is a drawing reproducing the display of the Silverlink handset and showing where the different icons are located. Values of States As defined above, each icon is described with 2 bits. These bits will be set and reset in the following way to indicate if the icon is on, off or blinking. Bitl Bit2 l=Blink - 0= NoBlink l=On - 0=Off Icon Byte KIcByl) Spkrl I Spkr2 | Slashl | Slash2 | Lockl | Lock2 | Shiftl | Shift2 Icon Byte 2 (IcBv2) Busyl I Busy2 jPubl |Pub2 | Privl |Priv2 | Pw l | PwT2 Icon Bvte 3 (IcBy3) Scrolll Scroll2 N.U N.U N.U N.U N.U N.U 5.2.2/Strings to be displayed The handset display is composed with a 12 digits display. In any case even if some strings are bigger than 12 characters, only the last 12 ones will be displayed. The kind of strings which have to be displayed are generally message coming from the network or the private base station to which the system is linked to. The CT2 module will append those 12 characters to the 2 icon bytes and the modem will retreive them to display them on the handset emulator (PowerBook screen). The format of these digits will be ASCII like the format used for the AT Λ KP commands. digl | dig2 | dig3 | dig4 | dig5 | dig6 | dig7 | dig8 | dig9 | digl0 | digll | digl2 5 .2 .2 / Status Format To summarise that, we will have the following status issued by the CT2 module on response of the AT A S1 command . |A|Tp |lcByl|lcBy2 |IσBy3|dl|d2|d3|d4|d5|d6|d7|d8|d9|dlO|dll|dl2|CR To get an idea of the extended status retreival by the modem, we will have the following sequence of commands and responses: AT Λ SKCR> -> <- AT ^ 8041263132333435363738393031320D means we have to change the state of the icons described in the first 3 bytes , and display "123456789012 " on the PowerBop screen. 6/ Application Status In order to let the Macintosh Application know the current status of the PowerBop system at any time, it can issue the same command as the one used by the modem to retreive the different status from the CT2 module, which would give the following sequences: 1/ S ? CR It will then return the standard PowerBop CT2 status in the following format, with all the fields encoded in Hex Code: StatusBytel |StatusByte2 |LIDl |LID2 |LID3 |LID4 |Blk#|CR OK <CR><LF> 2/ A S 1 ? CR It will then return the extended PowerBop CT2 status in the following format, with all the fields encoded in Hex Code: IcByl I IcBy2| IcBy3|dl|d2|d3|d |d5| |d5|dδ|d7 |d8|d9|dlO|dll|dl2 |CR OK <CR><LF> 6/ Ring Detection The hardware interface between the modem and the CT2 device for analog signals is 2 signals for Tranmit analog, 2 signals for Receive analog, and 1 signal for GND. It is what we call a 4 wires interface. In PSTN mode, the modem works in 2 wires mode. In that case the Ring information comes on what is the RXA signal in 4 wires mode. To keep the Ring detection as it is already implemented in the modem firmware, the CT2 device, will emulate the Ring signal, by modulating a special wire which will be routed to the Rxa Modem signal using an analog switch (See drawing below) . In that way the modem being in 2 wires mode at init time will see a normal ring. When all the link establishments will be done, the modem will pass then in 4 wires mode. (see figure 7) Interpretation of signal depending of the mode set Analog Signals - Hardware Interface : (see figure 8)

Claims: CLAIMS 1/ A computer, in particular a portable personal computer, suitable for remote communication via a telephone network, characterized in that it comprises in combination: a computer unit (11) including a central processor, storage means, input/output means, and means for inputting and displaying data; a modem (12) connected to the computer unit and suitable for being connected to the telephone network via a cord ( 12a); a transmitter/receiver circuit (14) suitable for establishing calls by radio with a remote site, likewise for accessing the telephone network; a control circuit (13) for the transmitter/receiver circuit; means provided in the computer for applying commands to the modem as selected from a predefined set of commands; cord call determining means provided in the computer for determining whether a telephone call via the cord is desired or in progress, and for producing a corresponding signal; means provided in the computer either for processing commands received in the modem or else for converting said received commands into specific commands for the control circuit and for applying these specific commands to the control circuit as a function of said signal; and means provided in said control circuit for processing said specific commands. 2/ A computer according to claim 1, characterized in that said transmitter/receiver circuit (14) is suitable for accessing said telephone network by previously establishing a radio link with a base station. 3/ A computer according to claim 1 or 2, characterized in that the cord call determining means are provided in the modem ( 12 ) . 4/ A computer according to claim 3, characterized in that the cord call detection means comprise detection means for detecting connection of the cord (12a) to the modem (12). 5/ A computer according to claim 4, characterized in that said detection means are constituted by means for determining the presence of a country identifier in said cord (12a). 6/ A computer according to any one of claims 1 to 5, characterized in that each of said specific commands comprises: a common prefix (AT) ; information ( " ) representative of the fact that said command is a specific command; and a command identifier. 7/ A computer according to claim 6, characterized in that said common prefix is identical to a common prefix (AT) for commands belonging to said predefined command set. 8/ A computer according to any one of claims 1 to 7, characterized in that the control circuit (13) is Originally designed for receiving manual instructions from a user producing instruction signals, in that one of said specific commands includes a command identifier followed by a string of characters, said identifier being representative of manual instruction simulation, and in that the control circuit is suitable for processing said characters of said string as though they constitute instruction signals resulting from giving manual instructions. 9/ A computer according to claim 8, characterized in that said manual instructions are constituted by keypresses performed on a keypad. 10/ A computer according to claim 9, characterized in that said string of characters is representative of a number to be dialed. 11/ A computer according to claim 8, 9, or 10, characterized in that said characters are in ASCII format. 12/ A computer according to any one of claims 1 to 11, characterized in that said control circuit (13) is originally designed to control display means, in that the control circuit is suitable for transmitting a message to the modem that includes a string of characters representative of information to be displayed on the display means, and in that the computer includes means for processing said character. 13/ A computer according to claim 12, characterized in that the means for processing said characters comprise means for providing a display on the basis of said characters. 14/ A computer according to any one of claims 1 to 13, characterized in that the modem includes means for detecting an incoming ringing signal, and in that the control circuit (13 ) includes means for generating a simulated ringing signal (ERING) and for applying it to the modem. 15/ A computer according to claim 14, characterized in that it further includes switching means (100) for switching commands under the control of the control circuit (13) and suitable for selectively applying to an analog signal input terminal of the modem either said generated simulated ringing signal or else analog signals as received by said transmitter/receiver circuit. 16/ A method for use in a computer, in particular a portable personal computer, comprising: a computer unit (11) including a central processor, storage means, input/output means, and means for inputting and displaying data; a modem (12) connected to the computer unit and capable of being connected to a telephone network via a cord (12a); a transmitter/receiver circuit (14) suitable for establishing radio calls with a remote site; a control circuit (13) for controlling the transmitter/receiver circuit; and means provided in the computer for applying commands to the modem, which commands are selected from a predefined set of commands, the method being intended to set up a remote call via said telephone network and being characterized by the following steps: it is determined whether a telephone call via the cord is reguested or is in progress, and a corresponding signal is produced; as a function of said signal, either received commands are processed in the modem, or else the received commands are converted into specific commands for the control circuit and said specific commands are applied to the control circuit; and said specific commands are processed in said control circuit.

Inventors: HEESCHEN DAVE, MARDINIAN OLIVIER, TAYLOR LARRY, HEESCHEN, DAVE, MARDINIAN, OLIVIER, TAYLOR, LARRY
Applicants: APPLE COMPUTER, HEESCHEN DAVE, MARDINIAN OLIVIER, TAYLOR LARRY, APPLE COMPUTER, INC., HEESCHEN, DAVE, MARDINIAN, OLIVIER, TAYLOR, LARRY
Application year: 1994
Main classification: H04Q7
IPC codes: H04M11, H04Q7